CD44 and endometriosis: A more recent, 2020 study, that evaluated CD44 expression in the endometrium and ectopic endometriotic lesions of women with and without endometriosis, surprisingly found lower levels of this cell-surface glycoprotein in the women with endometriosis compared to controls, with CD44 IHC analysis suggesting that it was mostly localized in the cytoplasm of glandular and stromal cells [2].